Try Sample:
Drop .crx or .zip extension file here
or click to browse from your computer (processed 100% locally in browser)
Extracting extension archive and analyzing manifest...
Declared Permissions
No special permissions requested
Host Permissions (Accessible Domains)
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Background Component
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Content Scripts
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Select a file from the explorer on the left to inspect its contents.
About Chrome Extension Source Viewer
Chrome Extension Source Viewer is an online developer tool designed to inspect, deconstruct, and examine the complete source code of any Google Chrome extension. You can enter a Chrome Web Store URL, provide an extension ID, or upload an existing .crx or .zip package directly from your computer.
The tool extracts the package in the browser, stripping CRX2 and CRX3 binary packaging headers to access the underlying ZIP archive. It analyzes manifest.json metadata, permissions, content scripts, and background service workers, and provides an interactive file explorer with CodeMirror syntax highlighting and automated code beautification.
Key features
- Direct Chrome Web Store & File Upload Support Fetch extensions directly via Chrome Web Store URLs (both chromewebstore.google.com and chrome.google.com) or 32-character extension IDs, or drag and drop local .crx and .zip files.
- CRX2 & CRX3 Automatic Header Stripping Parses binary packaging signatures and calculates offsets automatically, converting proprietary CRX archives into clean, standard ZIP archives readable by any file manager.
- Manifest V2 & V3 Security & Permissions Audit Parses manifest.json and _locales strings to display extension metadata, background service workers, injected content scripts, API permissions, and sensitive host matches.
- Interactive File Tree with Instant Search Navigate the extension folder structure with collapsible directories, file size indicators, file type icons, and real-time path filtering.
- CodeMirror Syntax Highlighting & Code Beautifier Inspect JavaScript, JSON, HTML, CSS, and Markdown with line numbers and syntax styling, and format minified or obfuscated bundles with one click using js-beautify.
- Image Preview & One-Click ZIP Download Preview PNG, SVG, WebP, and icon assets directly in the workspace, or download the full unpacked extension as a standard ZIP file ready for Chrome Developer Mode.
How to view Chrome extension source code
Follow these simple steps to inspect and download the source code of any Chrome extension.
- Provide extension URL, ID, or file Paste a Chrome Web Store detail URL, enter the 32-character extension ID, click a sample button, or drag and drop a local .crx or .zip file into the dropzone.
- Extract and review extension overview Click Fetch & Inspect to unpack the archive. Review the extension title, version, manifest version, and declared permissions in the overview banner.
- Explore folders and select source files Use the left file tree panel to navigate directories or filter by filename. Click any file to load its contents into the code viewer or media preview panel.
- Beautify code and export files Use the Beautify button to un-minify compressed scripts, copy snippets to your clipboard, or click Download as ZIP to save the entire unpacked package.
Usage tips
- In Manifest V3 extensions, background logic is located in background.service_worker, whereas Manifest V2 extensions use background.scripts or background.page.
- If an extension uses minified or bundled JavaScript (e.g., from Webpack or Vite), click Beautify Code in the editor toolbar to restore readable indentation and line breaks.
- You can test downloaded ZIP packages immediately in Chrome by opening chrome://extensions, enabling Developer mode, and clicking Load unpacked.
- Check the declared host_permissions and permissions badges in the overview card to see which domains and browser APIs the extension has access to.
Frequently asked questions
A CRX file is a ZIP archive prepended with a proprietary Google binary header containing magic bytes (Cr24), version info, and cryptographic signatures. This tool reads the binary header, calculates the exact byte offset where the ZIP payload starts, and unpacks the internal files using client-side JSZip.
Yes. Extensions are often compiled or minified for performance. The viewer includes an integrated beautifier powered by js-beautify that reformats JavaScript, JSON, CSS, and HTML files with clean spacing and indentation at the press of a button.
Yes. The viewer seamlessly inspects both Manifest V2 and modern Manifest V3 extensions, correctly detecting service workers, content script registrations, action popups, and declarative permissions.
When you drag and drop a local .crx or .zip file, all extraction, parsing, and code viewing happen 100% locally inside your web browser. When fetching by Web Store URL or ID, our server only proxies the download from Google servers to bypass browser CORS restrictions and immediately streams the raw package to your browser without storing it.
Download the extension as a ZIP file using the Download as ZIP button, extract the ZIP into a local folder on your computer, navigate to chrome://extensions in Chrome, enable Developer mode in the top right corner, and click Load unpacked to select the extracted directory.